The most common driveway paving materials are asphalt or concrete, which are smooth and seamless. A second option is becoming more popular with homeowners: driveways that are made of permeable paving materials.

In addition to being a less-expensive method, permeable paving allows water to flow through it rather than diverted to the nearest sewer.

Rainwater that falls off roofs, runs down hard-surface driveways and fills rivers, ponds and municipal water systems may start out fresh. But as it travels, it picks up debris from the roof, oil and fertilizer from driveways and sidewalks, and a wealth of garbage from the street. This adds pollution to our waterways, and creates extra work for water-treatment facilities.

The beauty of permeable paving is that water is absorbed through the paving before it can reach our water sources. With many permeable-paving options, you can save money and be environmentally responsible.

Permeable-paving products run the gamut from low to high tech. The simplest of them is grass. Like a path worn in the woods, grass that is constantly pressed down by vehicles will form a natural and permeable driveway.

Two thin paving strips can provide a path for car tires. You can also use permeable material such as gravel for the strips. Paving strips might seem a rather antiquated approach, but they have been gaining in popularity as homeowners look toward sustainable construction.

One of the most common methods of creating permeable driveways is the use of loose stones and gravel.

Gravel has been supporting traffic of all kinds for centuries, but a modern addition is the use of plastic grids. These are created using recycled grids or blocks that form a hard driving or walking surface, but still allow water to flow through. Grids can be filled with sand and soil or gravel. They are long lasting, easy to install and maintenance free.

Another approach is to use what are called open-cell concrete blocks to create permeable pavers. They function much like the plastic-grid systems. Open-cell concrete blocks allow water through, but they can handle heavy loads, too. The open cells are filled with topsoil and grass, and eventually the blocks become hard to distinguish from the surrounding area.

There are new types of concrete and asphalt that allow water to soak through as well. Permeable concrete and asphalt were developed specifically to allow pavement-style parking and driving surfaces while still addressing environmental concerns.

HomeWork is the weekly column by the Master Builders Association of King and Snohomish Counties’ Remodelers Council about home care, repair and improvements. If you have questions about home improvement, send them to homework@mbaks.com.

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